The FreeBSD port sysutils/bsdstats supports pkg_* tools, but does not support pkgng. pkgng will soon become the default package management system in FreeBSD, whereas pkg_* tools will soon become unsupported.
Thank you to Anton Shterenlikht for reporting this problem.
Fix: I've attached a patch for the port's files/300.statistics.in file. The patch adds support for pkgng while preserving support for pkg_* tools. The patch also includes instructions for removing pkg_* tools support when it's officially discontinued.
Patch attached with submission follows: